1. Field of the Invention
The present invention relates to a display driver integrated circuit, and more particularly, to a display driver integrated circuit using a ping-pong type sample/hold circuit.
2. Description of the Related Art
In liquid crystal displays (LCDs), a panel is driven by applying a predetermined gray voltage to both ends of the panel. The gray voltage denotes a voltage determined according to a gamma curve, and is thus referred to as a gamma voltage.
A gray voltage depends on a gamma curve which is applied to a corresponding LCD (more specifically, to an LCD panel included in the LCD). Different gamma curves are applied according to LCD panel manufacturing methods, LCD panel manufacturing companies, etc. In addition, a gamma curve exhibits non-linearity characteristics.
FIG. 1 is a block diagram of a conventional display driver integrated circuit 100. Referring to FIG. 1, the conventional display driver integrated circuit 100 includes a level shifter 110, a gray voltage generation unit 120, a decoder 130, and an amplifier 140. The level shifter 110 receives input image data DATA from an external source, changes the level of the input image data DATA to an appropriate voltage level, and outputs a result of the level change to the decoder 130. The gray voltage generation unit 120 generates a plurality of gray voltages and outputs the gray voltages to the decoder 130. The decoder 130 selects one of the gray voltages in response to the input image data DATA and outputs the selected gray voltage to the amplifier 140. The amplifier 140 amplifies the gray voltage output by the decoder 130, and outputs the amplified gray voltage to an LCD panel (not shown).
FIG. 2A is a block diagram of an area of the conventional display driver integrated circuit 100 of FIG. 1 when 6-bit input image data is input. FIG. 2B is a block diagram of an area of the conventional display driver integrated circuit 100 of FIG. 1 when 8-bit input image data is input.
Referring to FIGS. 2A and 2B, an area of the decoder 130 is greater when the 8-bit input image data is input than when the 6-bit input image data is input. That is, in the conventional art, the higher the number of bits of the input image data is, the greater the size of the decoder 130 becomes by geometric progression. Thus, as the number of bits of the input image data increases, the conventional display driver integrated circuit 100 increases in size.